1. Field of the Invention
The present invention relates to feeding of combustion air to a combustion device. In particular, the invention relates to air registers which surround a fuel nozzle and which deliver combustion air to be mixed with the fuel fed to the combustion device by the fuel nozzle. In this way a fuel-air mix is provided to support combustion.
2. Background of the Invention
In the burning of fuels using burners fed by air registers, it has become known in the industry to divide the combustion air into an inner ignition zone and an outer, supplemental zone which concentrically surrounds the inner ignition zone. The purpose of the divided zones is to separate the high intensity mixing necessary for good ignition stability at the center of the fire from the smoother air flow at the perimeter, where it is important to avoid the nitrous oxide production of a very hot, intense flame.
The present invention is directed to enhancing and improving multiple zone combustion by providing an air register apparatus, method, and overall arrangement in which enhanced control over the characteristics of the combustion in the inner and outer zones may be achieved.
The present invention extends and improves upon certain enhanced flow characteristics, flow measurability, and flow control as provided in U.S. Pat. No. 4,504,216 to Donald K. Hagar et al, which patent is hereby incorporated herein by reference. In that patent, an air register is disclosed utilizing an inwardly spiralling scroll passageway which organizes the air flow, which air flow may be measured and which is controlled by a simple upstream valve remote from the hostile environment of the furnace. Reference is made to the aforesaid U.S. Pat. No. 4,504,216 for a more complete discussion of this subject matter.
As further background, reference is also made to Chapter 9 of "Steam/Its Generation and Use" by the Babcock and Wilcox Company, 1978 ed., which is hereby incorporated by reference, and which discusses and illustrates the use of air registers for supplying combustion air to a combustion device. Again, reference is made to this Babcock and Wilcox publication for a more complete discussion of the background, context and environment of the present invention.